王欣梅, 刘雯君, 周宜开. 甲基汞暴露对出生后大鼠学习记忆及NMDA受体表达的影响[J]. 环境与职业医学, 2012, 29(1): 27-30.
引用本文: 王欣梅, 刘雯君, 周宜开. 甲基汞暴露对出生后大鼠学习记忆及NMDA受体表达的影响[J]. 环境与职业医学, 2012, 29(1): 27-30.
WANG Xin-mei , LIU Wen-jun , ZHOU Yi-kai . Effects of Postnatal Exposure to Methylmercury on Learning, Memory and Expression of NMDA Receptor of Rats[J]. Journal of Environmental and Occupational Medicine, 2012, 29(1): 27-30.
Citation: WANG Xin-mei , LIU Wen-jun , ZHOU Yi-kai . Effects of Postnatal Exposure to Methylmercury on Learning, Memory and Expression of NMDA Receptor of Rats[J]. Journal of Environmental and Occupational Medicine, 2012, 29(1): 27-30.

甲基汞暴露对出生后大鼠学习记忆及NMDA受体表达的影响

Effects of Postnatal Exposure to Methylmercury on Learning, Memory and Expression of NMDA Receptor of Rats

  • 摘要: 目的 研究甲基汞暴露对出生后不同生长期大鼠学习记忆能力及 N-甲基 -D-天冬氨酸(NMDA)受体mRNA水平表达的影响。

    方法 将出生后大鼠随机分组, 即 5 mL/kg生理盐水组和 5 mg/kg氯化甲基汞(MMC)染毒组,其中染毒组按生后不同生长时期分 4个亚组, 即 PND7、PND14、PND28和 PND60组, 连续 7 d灌胃染毒。采用 Morris水迷宫试验检测大鼠学习记忆功能的改变, 用原子荧光光度计检测脑组织汞含量、用逆转录 -聚合酶链式反应(RT-PCR)特异性扩增受体 NMDA的 2A、2B、2C亚基, 半定量分析 PCR产物凝胶电泳结果。

    结果 各染毒亚组在染毒后脑组织中汞含量明显高于对照组 (P < 0.01), 水迷宫试验后, PND28皮质组织及 PND60脑组织中汞含量明显高于对照组 (P < 0.01);Morris 水迷宫试验结果显示, PND7、PND14 染毒大鼠水迷宫测试潜伏期明显长于对照组(P < 0.01); PND14 染毒亚组海马和皮质中 NR2A mRNA 的表达明显低于对照组(P < 0.05); PND14 染毒亚组海马中 NR2B mRNA 表达明显低于对照组(P < 0.01); PND14染毒亚组海马和皮质以及 PND28亚组皮质中 NR2C mRNA表达明显高于对照组(P < 0.01)。

    结论 甲基汞对出生后 1、2周的大鼠学习记忆功能有明显影响, 其影响与脑组织 NMDA受体 2亚基 mRNA表达变化有关。

     

    Abstract: Objective To study the effects of postnatal exposure to methylmercury on learning, memory and the expression of N-methyl-D-aspartate (NMDA) receptor mRNA in rats.

    Methods The rats treated with 5 mg/kg methylmercury chloride (MMC) were taken as MMC-treated group and those with 5 mL/kg sodium chloride solution as control group, by oral for 7 consecutive days. The MMC-treated group was subdivided by different postnatal periods (PND7, PND14, PND28 and PND60) and tested for learning and memory with Morris water maze. The concentration of mercury was checked by atomic fluorescence spectrometry (AFS). Expression of NMDA receptor 2A, 2B and 2C subunits were measured by semi-quantitative reverse transcript polymerasechain reaction (RT-PCR).

    Results Mercury concentrations in both hippocampus and cerebral cortex were elevated significantly in the MMC-treated group (P < 0.01); while the level of mercury in cortex of PND28 and both cortex and hippocampus of PND60 was significantly higher in comparison with that of the control (P < 0.01). The latency of PND7 and PND14 MMC-treated rats in water maze was much longer than that of the control (P < 0.01). The levels of NR2A mRNA were significantly decreased in both hippocampus and cortex of PND14 subgroup (P < 0.05); the levels of NR2B mRNA were significantly reduced in hippocampus of PND14 subgroup (P < 0.01); and an increment of NR2C mRNA was observed in hippocampus of PND14 and in cortex of PND14 and PND28 subgroups (P < 0.01).

    Conclusion The first two weeks after birth is critical to methylmercury exposure, which would result in the impairment of learning and memory ability for life span. The altering expression of NR2 subunits is an influencing factor.

     

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